package cn.fu.security.rsa;

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

import javax.crypto.Cipher;

import org.apache.commons.codec.binary.Base64;

/**
 * @Title: MyRSA.java
 * @Package cn.fu.security.rsa
 * @Description: 非对称加密算法，也可用于数字签名（应用广泛） 比dh慢 数据加密&数字签名 公钥加密，私钥解密 私钥加密，公钥解密
 * @author zhangxiaofu
 * @Company www.viewhigh.com
 * @date 2016年8月21日 下午4:22:21
 * @version V1.0
 */
public class MyRSA {
	private static String src = "99fu";

	public static void main(String[] args) {
		jdkRSA();
	}

	private static void jdkRSA() {
		try {
			// 1,初始化密钥
			KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
			keyPairGenerator.initialize(512);
			KeyPair keyPair = keyPairGenerator.generateKeyPair();
			RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
			RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
			System.err.println("public key :" + Base64.encodeBase64String(rsaPublicKey.getEncoded()));
			System.err.println("private key :" + Base64.encodeBase64String(rsaPrivateKey.getEncoded()));

			// 2私钥加密，公钥解密 --加密
			PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
			KeyFactory keyFactory = KeyFactory.getInstance("RSA");
			PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
			Cipher cipher = Cipher.getInstance("RSA");
			cipher.init(Cipher.ENCRYPT_MODE, privateKey);
			byte[] result = cipher.doFinal(src.getBytes());
			System.err.println("私钥加密，公钥解密 --加密:" + Base64.encodeBase64String(result));

			// 3.私钥加密，公钥解密--解密
			X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
			keyFactory = KeyFactory.getInstance("RSA");
			PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
			cipher = Cipher.getInstance("RSA");
			cipher.init(Cipher.DECRYPT_MODE, publicKey);
			result = cipher.doFinal(result);
			System.err.println("私钥加密，公钥解密--解密：" + new String(result));

			// 4 公钥加密，私钥解密 -- 加密
			x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
			keyFactory = KeyFactory.getInstance("RSA");
			publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
			cipher = Cipher.getInstance("RSA");
			cipher.init(Cipher.ENCRYPT_MODE, publicKey);
			result = cipher.doFinal(src.getBytes());
			System.err.println("公钥加密，私钥解密 -- 加密:" + Base64.encodeBase64String(result));

			// 5 公钥加密，私钥解密 -- 解密
			pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
			keyFactory = KeyFactory.getInstance("RSA");
			privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
			cipher = Cipher.getInstance("RSA");
			cipher.init(Cipher.DECRYPT_MODE, privateKey);
			result = cipher.doFinal(result);
			System.err.println("公钥加密，私钥解密 -- 解密：" + new String(result));

		} catch (Exception e) {
			// TODO: handle exception
		}
	}
}
